The present invention relates to a swash plate compressor of the type disclsed in copending U. S. patent application Ser. No. 949,000, filed Oct. 5, 1978 which is assigned to the same assignee as this application.
The present type of compressor generally includes a cylinder which is formed with a plurality of axial bores. Double acting pistons are slidably disposed in the bores. A swash plate diagonally mounted on a shaft is connected to the pistons in such a manneer that rotation of the shaft and swash plate causes reciprocation of the pistons to compressively displace a fluid. Swash plate compressors are often used as refrigerant compressors for automotive air conditioning systems and the like.
In order to lubricate the swash plate, pistons etc. a lubricant chamber or sump is generally provided in the lower portion of the cylinder containing oil in which the swash plate is partially immersed. The swash plate spashes the oil onto the internal components of the compressor to provide lubrication.
The splash lubrication system is generally superior to a forced lubrication system which requires a separate oil pump, which is typically of the trochoidal type, since a separate oil pump adds to the mechanical complexity and cost of the compressor. However, a problem has existed heretofore in lubrication of the bearings which support the swash plate and drive shaft.
Such lubrication has generally been effected by means of oil entrained in the refrigerant fluid which is forced into the spaces between the shaft and bearings due to pressure created in the swash plate chamber during operation of the compressor. However, the pressure is insufficient during startup of the compressor to provide sufficient lubrication. This underlubrication, especially during the severe conditions of startup, often cause the shaft to score the bearings or even seize.
An attempt to overcome this problem, which constitutes the closest known prior art, is disclosed in U. S. Pat. No. 3,801,227. The prior art system connects an inlet chamber to the bearings through passageways. Oil separated from the refrigerant fluid in the inlet chamber flows down through the passageways to lubricate the bearings.
However, this prior art system does not completely solve the problem since the vacuum in the inlet chamber works against the gravity flow of oil through the passageways and results in insufficient lubrication of the bearings.